Aaron Gustafson wrote a well-reasoned post about Progressive Enhancement vs. Hardboiled Design yesterday. In it he describes Progressive Enhancement more eloquently than I can (although he also uses a house analogy), and explains how it's not at odds with the "Use the latest and greatest technology right now" approach that Hardboiled Web Design champions. Being a big fan of both approaches, this made me very happy. There's no reason not to use the latest tech, as long as it's applied in a stepped, responsible, manner.
Progressive Enhancement is all the more important in the industry at the moment because of the meteoric rise of Mobile First Responsive Design. Applying Progressive Enhancement in this context means starting with a small screen, low capability device, and adding features as screen size and device capability increases.
Aaron's post jumped off from A plea for progressive enhancement, which reminded me to hit up Yiibu's excellent Slideshare page. I've grabbed copies of the most recent three, which I somehow missed, and have them lined up for reading matter when I travel later this week.
Adaptive Web Design (Aaron's book) is an excellent read, and I highly recommend it. It's clear, concise, and offers excellent practical advice. I find that it goes very well with Filament Group's Designing with Progressive Enhancement. Adaptive Web Design was quite a fast read, but great at getting the ideas across and making them stick. Designing with Progressive Enhancement is dense and a bit heavy going at times, but is an excellent resource and is jam-packed with fully worked examples. I would call both required reading!